12

Question 1

What is the endosymbiosis theory? Who proposed it? What are the evidences to support endosymbiotic theory for eukaryotic origins?

Answer 1

Membrane infolding to form many organelles (prokaryotes have infoldings of plasma membrane to use for respiration, photosynthesis)
Mitochondria & chloroplasts? –Endosymbiosis theory

Proposed by Lynn Margulis - 1967

Supports for this theory:
Same size as bacteria
Replicate on their own
Transcription/translation machinery
Double membranes
Separate, circular DNA w/out histones
Some protist chloroplasts contain peptidoglycan

Question 2

Protists are

Answer 2

paraphyletic, diverse, abundant and often aquatic

Question 3

What are the general characteristics of protists? Types of protist locomotion; modes of nutrition; external structures; symbiosis; phytoplankton (how they play a role in the food web); Protist reproduction; Alternation of generation – know which stages are haploid (n) and which are diploid (2n) in the protist life cycle

Answer 3

Locomotion~~Amoeboid motion
Cytoskeletal movement

Flagella/Cilia~~Homoplasy w/ bacterial flagella
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Nutritional modes:
Photoautotroph
Chemoheterotroph
Mixotroph
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external structure:
Cell wall
Shell
Pellicle
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Sybiosis:
Many photosynthetic protists live symbiotically with other organisms 
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Phytoplankton
Photosynthetic small organisms that live near the surface of oceans or lakes
Protists (+ prokaryotes)
Diatoms are the leading primary producer in oceans
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Usually asexual reproduction
Sexual reproduction occurs sometimes
Seasonally
Scarce resources

Variety of life cycles
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Question 4

What are some of the major protists and their features

Answer 4

Red Algae-Phycoerythrin
Absorbs blue light
Alternation of Generations
Important in reef habitats
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Green
Diverse
Unicellular to multicelluar
Marine, freshwater, terrestrial
Alternation of Generations (some)
Closest relative of terrestrial plants
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Brown
Multicellular
Largest & most complex algae
Alternation of Generations
Important habitat
Sargasso Sea
Kelp
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Dinoflagellates
Phytoplankton
Many mixotrophic & heterotrophic
Some cause Red Tides
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 diatoms
Found in almost all aquatic habitats
Leading primary producers of oceans
Diatomaceous earth- Silica shells- form deposits used as Filtration substance, insecticide, cat litter, dynamite component, cosmetics (silica shells)
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Slime molds
Plasmodial 
Large supercell with many nuclei
Form spores when food is scarce
Cellular Slime Mold
Unicellular most of their lives
Multicellular swarms when food is scarce
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Amoebas
Free-living amoebas
Parasitic amoebas (entamoeba)
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Diseases:
Giardia
Intestinal parasite

Trichomonas vaginalis
Causes Trichomoniasis
Most common curable STD in young, sexually active women
Increases risk of HIV 
	infection and problems 
	during pregnancy

Trypanosomes
Chagas disease, Sleeping sickness
Affects nervous system & organs
Transmitted by insects

Plasmodium species
Apicomplexan
Toxoplasma gondii
Toxoplasmosis
Transmitted through ingestion of infected meat or cat feces
Most people have no symptoms or illness
Dangerous for fetus & immunocompromised

Malaria
Transmitted by 30-40 different mosquito spp.